--- id: CVE-2026-68123 title: 'kernel: openvswitch: fix GSO userspace truncation underflow (CVE-2026-68123)' summary: >- A flaw was found in the Open vSwitch component of the Linux kernel. This vulnerability arises from an underflow condition when handling Generic Segmentation Offload (GSO) packets in userspace. A length calculation error can lead to a buffe… severity: high cvss: 7 cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H' cvssSource: vendor cwe: CWE-787 vendor: Red Hat product: Red Hat Enterprise Linux BaseOS (v. 10) affected: - enterprise_linux 7 - enterprise_linux 8 - enterprise_linux 9 - openshift_container_platform 4 - enterprise_linux 6 - 10base_smtv - enterprise_linux_appstream_v_10 - enterprise_linux_appstream_v_9 - enterprise_linux_baseos_v_10 - enterprise_linux_baseos_v_9 - enterprise_linux_codeready_linux_builder_v_10 - enterprise_linux_codeready_linux_builder_v_9 - enterprise_linux_hidden_v_10 - enterprise_linux_real_time_for_nfv_v_10 - enterprise_linux_real_time_for_nfv_v_9 - enterprise_linux_real_time_v_10 - enterprise_linux_real_time_v_9 patched: - 10base_smtv - enterprise_linux_appstream_v_10 - enterprise_linux_appstream_v_9 - enterprise_linux_baseos_v_10 - enterprise_linux_baseos_v_9 - enterprise_linux_codeready_linux_builder_v_10 - enterprise_linux_codeready_linux_builder_v_9 - enterprise_linux_hidden_v_10 - enterprise_linux_real_time_for_nfv_v_10 - enterprise_linux_real_time_for_nfv_v_9 - enterprise_linux_real_time_v_10 - enterprise_linux_real_time_v_9 published: '2026-08-10' updated: '2026-10-23' sourceUpdated: '2026-10-23T10:54:36+00:00' source: CSAF sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-68123.json' references: - url: >- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-68123.json - url: 'https://access.redhat.com/security/cve/CVE-2026-68123' - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2513451' - url: 'https://www.cve.org/CVERecord?id=CVE-2026-68123' - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-68123' - url: >- https://lore.kernel.org/linux-cve-announce/2026081056-CVE-2026-68123-49d8@gregkh/T - url: 'https://access.redhat.com/errata/RHSA-2026:81406' - url: 'https://access.redhat.com/errata/RHSA-2026:81552' - url: 'https://git.kernel.org/stable/c/50a6a85f3d6b1d22d8436848606cdef5d2c490b4' - url: 'https://git.kernel.org/stable/c/2623c48cc3a8da9a1886fd8f65c0e348f4406fd6' - url: 'https://git.kernel.org/stable/c/e211b081901ffca76674082c73eeaed53524c369' - url: 'https://git.kernel.org/stable/c/a16eaaf7c0b0ccdef6166707d90ffbc6eebf6855' - url: 'https://git.kernel.org/stable/c/fbfa3ad2ad6f3a5624aba5211c46290fb98cc9dc' - url: 'https://git.kernel.org/stable/c/100a23b1613e9218e0af654ef102352c713f0263' - url: 'https://git.kernel.org/stable/c/ea85dbcbe8d4056ecb54352f97743d138ea4c407' - url: 'https://git.kernel.org/stable/c/4032f8ed10fcb84d41c508dfb04be96589f78dfe' tags: - csaf - vex - red-hat - cve.org - score-dispute epss: 0.00552 epssPercentile: 0.45927 ssvc: exploitation: none automatable: 'yes' technicalImpact: total timestamp: '2026-10-16T15:44:13.520896Z' scores: vendor: 7 cna: 9.8 ingestedAt: '2026-10-16T17:24:46.842Z' --- ## Overview A flaw was found in the Open vSwitch component of the Linux kernel. This vulnerability arises from an underflow condition when handling Generic Segmentation Offload (GSO) packets in userspace. A length calculation error can lead to a buffer underflow when data is processed by the `skb_zerocopy()` function. This issue could result in memory corruption, potentially leading to a denial of service or other unpredictable system behavior. ## Vendor advisories - **RHSA-2026:81406** · Red Hat · fixed in: 10Base-SMTV, Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10), Red Hat Enterprise Linux Hidden (v. 10), Red Hat Enterprise Linux Real Time for NFV (v. 10), … · released 2026-10-12 · [advisory](https://access.redhat.com/errata/RHSA-2026:81406) - **RHSA-2026:81552** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux BaseOS (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9), Red Hat Enterprise Linux Real Time for NFV (v. 9), Red Hat Enterprise Linux Real Time (v. 9) · released 2026-10-13 · [advisory](https://access.redhat.com/errata/RHSA-2026:81552) - **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4, Red Hat Enterprise Linux 6 · no fix planned: Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-10-23 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-68123.json) **kernel: openvswitch: fix GSO userspace truncation underflow** — rated Important by Red Hat. Released 2026-08-10, updated 2026-10-23. Affected: - Red Hat Enterprise Linux 7 - Red Hat Enterprise Linux 8 - Red Hat Enterprise Linux 9 - Red Hat OpenShift Container Platform 4 - Red Hat Enterprise Linux 6 Fixed: - 10Base-SMTV - Red Hat Enterprise Linux AppStream (v. 10) - Red Hat Enterprise Linux AppStream (v. 9) - Red Hat Enterprise Linux BaseOS (v. 10) - Red Hat Enterprise Linux BaseOS (v. 9) - Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) - Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) - Red Hat Enterprise Linux Hidden (v. 10) - Red Hat Enterprise Linux Real Time for NFV (v. 10) - Red Hat Enterprise Linux Real Time for NFV (v. 9) - Red Hat Enterprise Linux Real Time (v. 10) - Red Hat Enterprise Linux Real Time (v. 9) No fix planned: - Red Hat Enterprise Linux 7 - Red Hat Enterprise Linux 8 - Red Hat Enterprise Linux 9 - Red Hat OpenShift Container Platform 4 Not affected: - Red Hat Enterprise Linux for NVIDIA 26 - Red Hat OpenShift Container Platform 4 ## Remediation For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 The system must be rebooted for this update to take effect. Red Hat recommends treating all kernel errata as security-relevant. Given the kernel's fundamental role, any bug has a higher chance of impacting system security, even if that impact only becomes clear after a fix is published. Therefore, Red Hat prioritizes delivering fixes that improve our customers' overall security posture. Because of this proactive approach, a patch may be associa… https://access.redhat.com/errata/RHSA-2026:81406 For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 The system must be rebooted for this update to take effect. Red Hat recommends treating all kernel errata as security-relevant. Given the kernel's fundamental role, any bug has a higher chance of impacting system security, even if that impact only becomes clear after a fix is published. Therefore, Red Hat prioritizes delivering fixes that improve our customers' overall security posture. Because of this proactive approach, a patch may be associa… https://access.redhat.com/errata/RHSA-2026:81552 Workarounds / mitigations: - Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.